1. Field of the Invention
The present invention relates to a guide device for a flexible linking member passing into a bicycle frame to link a control member carried by bicycle handlebars to a receiver.
2. Description of the Related Art
The bicycle derailleur gears and brakes are generally controlled by the cyclist using control members carried on the bicycle handlebars. To actuate the brakes or derailleurs respectively, the control members are linked thereto by a flexible linking member that conventionally comprises a cable fixed to the frame of the bicycle. In this case, the control means are entirely mechanical. Battery-powered electromechanical control means are also available nowadays, in particular for controlling a bicycle derailleur gear, and in this case the control members are linked to an electrical receiver via linking means in the form of electrical wires.
Hydraulic control means are also available, in particular for controlling a hydraulic brake, and in this case the control means are linked to a hydraulic receiver via linking means in the form of Durit© pipes, generally made of rubber reinforced with textile or metal layers.
All of these control means require the use of linking members in the form of cables, electrical wires or pipes.
Instead of attaching these linking members conventionally to the external faces of the bicycle frame, bicycle manufacturers nowadays often choose to pass these linking members through the inside of the different tubes that make up the bicycle frame, whenever possible. This results in a final product that is more aerodynamic and more aesthetic, and in which the linking members are well protected.
However, there is nonetheless a critical zone which is the front of the bicycle because practically all of the linking members coming from control members carried on the handlebars enter the front portion of the frame in order to pass through certain tubular elements of same. In this regard, the linking member that links the control member of the front brake to the front brake runs, in the case of a brake built into the fork, advantageously into the bicycle stem and then into the fork steerer before reaching the brake.
The other linking members coming from the handlebars enter the frame further away through a respective opening, often a lateral opening, provided near to the front end, either of the horizontal tube of the frame, or of the diagonal tube of the frame, depending on the location of the member to be controlled.
In general, a head tube forming part of the bicycle frame, and the fork steerer tube installed therein do not leave much room for the linking members to pass through. In this regard, it should be noted that electrical wires are easy to integrate as they are very flexible and of limited diameter, unlike cables and pipes, which cannot have very small radii of curvature. The concept of head tube should be understood in its broadest sense as a tubular element able to receive a headset and through which a fork steerer can be passed.
Document DE 20 2013 005 555 U1 describes a guide device for a flexible linking member passing through a tube of a bicycle frame, in particular a head tube. This device includes an insert in the form of a plate built onto one side of the head tube. This insert is seated in a cut-out substantially halfway up the head tube. The insert is secured in the cut-out using a screw and it has several channels to enable functional elements such as Bowden cables to pass through. The channels open outwards on inlet openings for the functional elements.
One drawback of this device is that it requires a head tube with a relatively large width to provide sufficient space to incorporate this device, which is wide. For this reason, this device cannot be positioned at the top close to an upper bearing of the headset arranged in the head tube, whereas it would be preferable to be able to insert the linking members into the frame as high up as possible to minimise the length of the linking members outside the bicycle frame, between the control members and the inlet openings in the frame.